Space packing felt



July 24, 1934. H J. LOWE 1,967,444

SPACE PACKING FELT Filed July 8, 1931 @Hof/1412,13

Patented July 24, 1934 UNITED STATES yMTENT OFFICE 1 Claim.

This invention relates to space packing felt such as used in the art ofprinting.

Inthe formation of stereotype plates it is necessary to place a mat in acasting box and 5 subsequently pour the molten metal so. as to ll theimpressions in the mat and produce a -plate of the required shape havingthe desired raised printing faces.

It frequently happens that the mat provides for extensive blank spaceson the printed surface and where these spaces are to be produced the matis formed with areas of proper shapes and proportions which arefree'from impressions. Unless these portions of the mat are providedwith some kind of rm packing they will tend to bulgev or sag under theweight of the metal being supplied to the casting box. Consequently thedepression formed in the stereotype plate will not be of uniform depthbut will be provided with raised portions which will tend to makeimpressions, thereby producing what are commonly known as nigger headsin the spaces which should bekept clear. Plain strips of backing orspacing felt have been used for filling the spaces approximately of therequired shapes and sizes and aiiixed to the mat by an adhesive. Thisprocedure has been satisfactory when the printing has been done with aflat plate. However when a tubular or semi-cylindrical press is operatedsome difficulties are encountered. For example, if large space cavitiesin the mat are to be backed, the felt must be aixed to the mat at theproper places in narrow strips or small pieces. Unless these portions offelt are arranged along lines parallel with the axis about which the matis to be bent they will act to stiffen the mat to an undesirable extentwhen placed in the casting box and cause the formation of an imperfectstereotype. Obviously in order to apply a, numberof narrow strips orsmall pieces in this' manner within the space cavities a considerabletime is consumed and expert service is required. All of this .greatlyincreases the cost of producing a plate.

It is an object of the present invention to provide a spacing felt whichcan be produced in large sheets and cut or torn quickly to form a singlepiece for filling a large` space cavity, the felt being so made that itwill not yadd undesirable rigidity to the mat when bent to proper shapefor casting. A

Another object is to form the sheet material so that it can be quicklytorn to the desired shape 55 and proportions.

mentioned. These have been torn into piecesv (Cl. 15d-45.5)

With the foregoing and other ob'jects in view which will appear as thedescription proceeds, the invention resides in the combination andarrangement of parts and in the details of construction hereinafterdescribed and claimed, it being understood that changes in the preciseembodiment of the invention herein disclosed may be made within thescope of what is claimed without departing from the spirit of theinvention.

In the accompanying drawing the preferred form of the invention has beenshown.

In said drawing:

Figure 1 is a perspective view of a portion of a sheet of spacing felthaving the present improvement.

Figure 2 is a similar view showing a modification.

Figure 3 is a view of another form.

Figure 4 is an enlarged section through a portion of the sheet shown inFigure 1.

Figure 5l is a plain view of a portion of a curved mat having the spacecavities backed by the material constituting this invention. A

Figure. 6 is a section on line 66, Figure 5. Figure 7 is a sectionthrough a modified form of felt.

Referring to figures by characters of reference, 1 designates a. sheetof ordinary spacing felt one side of which has a film 2 of adhesive. Theother surface of the sheet is formed with crossed cuts or scores 3 whichdivide the sheet into rectangular outlines whereby the sheet can bereadily bent or curved in either of two directions with the'scores inthe outer or convex face. Instead of weakening the sheet material bymeans of score lines, crossed lines of perforations 4 can be used orcrossed rows of slits 5 can be employed. In these last two forms,illustrated in Figures 2 and 3, the sheet material, when bent alongcurved lines, will break partly through between the perforations orslits so that the opposite or coated surface can be fitted easilyagainst a convex surface Without adding undesirable rigidity thereto.

A mat has been shown at 6 in Figures 5 and 6 and, in addition to theimpressions 7 formed therein by type or the impression 8 formed by acut, there are extensive space cavities 9 extending around and betweenthe backs of said impressions. These large space cavities must be lledwith backing material before the metal is poured in the 'formation of astereotype plate 10. Consequently while the mat is at and inverted, theoperator tears out the largest possible strips or portions of the sheetspacing felt and, after moistening the adhesive, applies it to the spacecavities in the mat with the weakening lines of the material outside andextending longitudinally and transversely of the mat. Thus when the faceof the mat is bent to fit properly in a curved casting box the sheetwill iiex along these weakening lines causing the scores 3 to gap or theouter surface of the material in Figures 2 and 3 to crack or breakbetween the perforations or cuts.

"While each cavity can be properly lled or backed, as explained, thematerial used for that purpose will not renderethe mat too rigid.Gbviously the sheet material can easily be torn into small strips orsquares for use in small cavities but the material is more especiallyadvantageous because it can be placed in large pieces within large spacecavities, thereby greatly reducing the time and labor otherwiseconsumed.

in figure 7 I have shown a felt made up of a number of squares or blocksof material indicated at 10 and arranged in rows as in Figure 1. Theseblocks are joined by an adhesive 1l to a sheet of soft, flexible paperl2 which can be torn easily and this sheet, in turn, has an adhesive lm13 for attaching it to a mat.

By forming the felt in this manner it can be torn easily to proper sizewithout producing a rough or feather edge. The term felt used. in thisapplication is to be construed as applying to any kind. of materialwhich might be used for space packing:

What is claimed is:

Space packing felt for use on either flat or cylindrical surfaces of amat comprising a sheet of material having crossed lines or^ weakeningincisions in one surface, the other surface being reely, bendable toconcave form in either of two directions determined by said lines, and alayer of material upon the latter surface having an exposed adhesivesurface.

HERBERT J. LOWE.

'MEG

